I also dropped this stuff into an FAQ entry for future reference:
http://doc.pfsense.org/index.php/Remove_F1_Boot_Prompt
And the debug should really be =16, not 0x16, my memory was fuzzy on that one so I looked it up again. It worked with 0x16 but that may be why the debug messages were printing, since it wasn't quite the right mode, it had more debug info turned on.